Other names

2-Amino-4- (ethylcarbamoyl) -butyric acid, 5-N-ethylglutamine, gamma-glutamylethylamide, L-theanine, L-theanine, N-ethyl-L-glutamine, Teanina, Théanine.


Theanine is an amino acid (the building block for proteins) found in green tea. L-theanine (or L-gamma-glutamylethylamide) was discovered in 1949 and accounts for 1% to 2% of the dry weight of tea leaves. It exists only in free form. It was developed by the enzymatic method of obtaining synthetic L-theanine (Suntheanine).
People use theanine to treat anxiety and high blood pressure, to prevent Alzheimer’s disease and to improve the effectiveness of cancer treatment.

Principle of action

Theanine has a chemical structure very similar to glutamate, a natural amino acid in the body that helps transmit nerve impulses to the brain. Some of the effects of theanine appear to be similar to glutamate, and some effects appear to block glutamate.


L-theanine can help relieve stress by causing a relaxing effect without drowsiness, and can also have immunological symptoms. Theanine can also affect the cardiovascular system and play a preventive role in cancer; however, limited clinical information is available to support these claims.
Prevention of dementia, including Alzheimer’s disease. Treatment of high blood pressure. Improving the effectiveness of cancer drug treatment.


Theanine MAY BE SAFE with short-term use. Theanine is used once a week for 3 weeks. It is not known whether it is safe to use for a longer period of time.


Studies reporting an anti-anxiety effect used single doses of theanine from 200 to 250 mg.
The appropriate dose of theanine depends on several factors, such as the age of the user, health and several other conditions. There is currently insufficient scientific information to determine the appropriate dose range for theanine. Keep in mind that natural products are not always safe, and dosage can be important. Be sure to follow the appropriate instructions on the product labels and consult your pharmacist or doctor or other healthcare professional before use.